Iguanodon

Iguanodon Is The Second Most Popular Dinosaur Ever Discovered

Iguanodon is ranked so highly on the Paleontologist charts because it was the second dinosaur to ever be labeled. Named with a Greek term meaning “Iguana tooth,” Iguanodon fossils were at first mistaken for a species of a different category, nearly missing the chance to be named at all. They’re the most studied when it comes to dinosaur history, maintaining years of popularity because of their catchy title. Below we’ll explore significant aspects of the dinosaur behind the name.

Quick Facts

Name

Iguanodon

Prehistoric Era

Early Cretaceous

Classification

Herbivore

Order

Ornithischia

Suborder

Ornithopoda

Weight

4.5 metric tons (5 short tons)

Length

7.9 meters (26 ft)

Height

2.7 meters (9 ft) at the hips

Maximum Speed

9-12 mph

Territory

Europe, Northern Africa, & USA

What Did Iguanodon Look Like?

Image Courtesy of Flickr User HokutoSuisse

Iguanodon Was A Cretaceous Period Archosauria Herbivore

Iguanodon was an herbivore from the late-Cretaceous Period; this indicates that the Iguanodon was a pack animal, often foraging for leaves and berries within the protection of 3-4 others. While paleontologists originally believed the Iguanodon was a bipedal dinosaur, it was later discovered that the leg and arm joints moved to fit that of a four-legged runner. This means that the dinosaur was capable of running on two legs like most carnivores or, to gain leverage, could maneuver on four legs like the majority of their fellow herbivores. However, topping off at 9 feet tall, the Iguanodon towered above several species of would-be predators, indicating that these animals were rarely subjected to being hunted while in their groups; therefore, it’s believed that only stray juveniles would have used the skill of running on two legs to escape being another dinosaur’s dinner.

Physical Attributes of Iguanodon

Iguanodon could grow to be 9 feet tall, weighing in around 5 tons with a length of almost 33 feet. It was a massive dinosaur! They were four-fingered with the addition of a thumb-spike on each “hand” and their feet were three-toed with strong, slender arches and wide heels for traction. A bulky body added to their intimidating height and width with a long, stiff tail being used for protection and counter-balance. The Iguanodon’s legs were longer than their arms by at least 3 inches; however, they could easily transform from a bipedal runner to a four-legged galloper.

Image Credit to Ballista via Wikimedia Commons

The Thumb-Spikes of Iguanodon

The Iguanodon thumb-spikes have perplexed archeologists since the dinosaur’s initial discovery. The spike was cone-shaped, measuring 2-6 inches long with a sharp point and significant width. The original discoverer, Gideon Mantell, put the spike on the completed Iguanodon replica’s nose at first; however, it didn’t fit properly and looked misplaced. The grooves where the spike would fit snugly into the Iguanodon’s thumb were found shortly thereafter, but the use for these thumb-spikes is still unknown.

Speculation suggests the thumb-spikes were implemented for cracking open hard-shelled nuts or protecting the Iguanodon from predators. There’s also debate that the spikes could have been a mating selection method, allowing the males with the larger thumb-spikes to be chosen as ideal mates for their sheer size and ability to protect their offspring.

The Mistaken Identity of Iguanadon

When Iguanodon was first discovered, the naturalist who stumbled upon the fossil was quick to think that the teeth and bones were from an ancient giant crocodile. For years, scientists ran with the idea that they were chasing clues to a species that would closely resemble one of today’s most-famous reptiles. Crocodiles and alligators were studied in comparison to the fossils that were uncovered, until researchers and archeologists decided these creatures would be more apt to be related to Iguanas. This was a closer thought, but still inaccurate.

Up until the early 19th century, Iguanodon was depicted as much larger modern Iguanas; the coloring and scales were exactly the same, and these dinosaurs didn’t have an identity of their own until the fossils were actually pieced together. After the fossils were properly placed, the Iguanodon began to resemble a new animal rather than one that already existed.

What Did Iguanodon Eat?

As an herbivore, the Iguanodon ate plants, berries, and some nuts. The sharp beak on the front of their mouth was completely toothless, but Iguanodon cheeks were packed with sharp teeth for grinding tough plant materials. Each tooth was curved, measuring 2 inches long from top to bottom with jagged tips for chewing.

How Did Iguanodon Move?

Iguanodon was a fast animal with the advantage of choosing to walk on two legs or all four. While scientists can’t be 100% positive of the dinosaur’s exact speed, they’ve based their opinions on the height, length, and bone mass of the animal’s legs. Some fossilized trackways discovered 4 inches in the sand around the Iguanodon bones indicates they could move quickly at 15-20 kilometers per hour. That’s 9-12 mph!

Predators of Iguanodon

Iguanodon was considered to be a dinosaur of higher intelligence. Traveling in packs and having the option of running at high-speeds, these animals didn’t have to contend with many predators. Sometimes stray juveniles would be caught by lone carnivores but other than that, the Iguanodon did well with avoiding destruction of their species. On the food chain, they literally grew bigger than some of the most vicious carnivores; a fact that was intimidating to potential predators, especially when the Iguanodon would migrate in groups.

The Discovery of Iguanodon

Image Courtesy of Flickr User KitLKat

Where Did Iguanodon Live?

Iguanodon has been discovered allover the world, showing that these creatures were capable of adapting to a wide range of climates. The largest fossilized finds have been in Belgium, England, and Germany where the Iguanodon are believed to have roamed in packs 125-135 million years ago. Continents were forming and lands were parting around the late-Cretaceous Period, meaning these animals were forced to evolve in conditions that were heading towards the first Ice Age. It’s rumored that sub-species of Iguanodon made their way to all parts of the world, excluding what is now Antarctica.

Iguanodon Specimen Discovery

In 1822, a British naturalist by the name of Gideon Mantell found what he believed to be the fossilized remains of a giant crocodile. While the teeth were the only things he discovered, 30 years of research and further findings of actual bone and other fossilized matter suggested that paleontologists and archeologists were dealing with a new species of at least a 3 ton dinosaur.

Better speciments soon followed, beginning with a major discovery of a what appeared to be a bonebed in Bernissart, Belgium. Two coal miners were responsible for the find of what was later deemed to be at least 38 fossilized Iguanodon. While not yet named, these fossils and bones gave new insight into this dinosaurs length, height, habits, and nature. It wasn’t until 1872 that scientists attempted to gather all the dino evidence in one place to draw a final conclusion as to what they had uncovered. Later, the Iguanodon was given a proper name, becoming the second dinosaur with it’s own genre and numerous sub-categories for similar species.

Why Is Iguanodon Important?

Iguanodon is considered the ‘saving grace’ of the paleontological world. These dinosaurs gave hope to researchers who were becoming frustrated from the lack of new discoveries. As the second dinosaur to be named, Iguanodon was the third to be presented to the public in a museum for fossilized artifacts. The fossils that have been found since then were placed in sub-categories and compared to the Iguanodon. Without the iguanodon, there would be no basis for comparison when it comes to new Archosauria fossils discovered.